Monday, 29 September 2014

Crostata alla marmellata (jam tarte) and a lesson on how to make pasta frolla

Crostata alla marmellata (jam tarte)

Crostata, the Italian word for tart or pie, is one of the most popular and loved sweet baked goods in Italy. It is prepared in almost infinite forms and varieties, with local / regional versions, and it is possible to find at least one type of crostata in every single bakery, patisserie, bar and café all over the country. But also the homemade version is very common: almost all families have their own recipe which is usually handed down from mother to daughter. The peculiarity of crostata is the pastry dough used, the pasta frolla, that is the Italian take on the sweet shortcrust pastry - and this why I like to call it with the Italian name.
Pasta frolla is probably the most used basic dough in Italian pastry-making for preparing shells or closed pies, that can be topped or filled with an infinite variety of ingredients: custards, fruits, chocolate ganache, ricotta-based fillings, caramel sauce, or even savory fillings; the most simple of all possible fillings is jam or marmalade. This "basic" version of the crostata is absolutely my favorite breakfast and I make it very often. And it is so tasty and comforting that any moment of the day is perfect for having a little wedge of it.
But even if apparently simple, pasta frolla is not really the easiest of doughs to prepare or handle. Considering my passion for any kind of crostata I wanted to know more about pasta frolla and to discover how to make it in the best way, and studied a bit. Even if I like improvisation in the kitchen, cooking and especially baking and making pastries, I'm afraid, is all a matter of chemistry and physics. I do not want to bother anybody with a scientific treatise, but I like to share some basic pieces of information that can help anybody to make a good pasta frolla, which is a basic pastry dough perfect for almost any kind of sweet (and some savory) tarte one can imagine (and if someone has not understood yet, it is my favorite one). And once one masters just a little bit of this topic, no store-bought pastry shell or pastry dough will ever after been taken into consideration when deciding to make a tarte or a pie.

"Frolla", in the Italian language, seems to have the same etymology as "frollare" (the Italian word for dry-aging) that is the process of preparing beef meat for consumption, in order to break the connective tissue and make the meat more tender and tasty when cooked. All this to mean that pasta frolla characteristics improve after a relatively long rest in the fridge (minimum one hour, better about 24 hours)  before being used and baked.
But "frolla" also means something like friable, crumbly, and in fact a good pasta frolla should be solid and hard enough to hold the filling but with a melt-in-the-mouth texture.
Few ingredients are required for this dough, but for a really good result they should be best quality, organic if possible ingredients you can find. The ingredients are: flour, fat (mainly butter), sugar, eggs and flavors.
Flour: flour should be low in gluten because high-gluten flour results in tough, brittle pastry dough when it is mixed with the liquids. The best is pastry or cake flour (Italian flour 00) but also all-purpose flour is fine (in this case better to add some corn or potato starch to reduce the gluten content). For more rustic texture other types of flour can be used: spelt, cornmeal or wholegrain wheat flour. In the so called "past frolla Napoli" part of the flour - around 10 percent- is substituted for almond flour (or finely ground almonds). Also when using a flour low in gluten (values between 9% and 12% protein are fine), in order to obtain a friable and crumbly pastry, it is important to handle the dough as less as possible when adding liquid ingredients: when the dough comes together stop working it and let it rest in the fridge.
Part of the flour (never more than 15%) can be substituted for cocoa in order to have a dark pasta frolla (in this case better to use whole eggs instead of yolks: see the eggs paragraph). In some recipes a small quantity of baking powder is added for a softer pastry.
Fats: the best fat for pasta frolla is butter (but also vegetable fats or oils are admitted). The quantity depends on the type of frolla desired, but there is a range, calculated as a percentage of the flour weight, that should be respected: min 30% - max 70% of flour weight in the pasta frolla for tartes and pie; min 50%-max 80% in the so-called whipped pasta frolla, used mainly for making cookies or tartellettes and shaped with a piping bag.
When butter is 50% or more the weight of flour, the pasta frolla is classified as sablè.
It is also important to handle the butter at a temperature around 13°C (at a lower temperature, for example the fridge temperature that is around 4°C, fat would be too cold to amalgamate with the other ingredients, then resulting in a dough with small pieces of butter inside), at a higher temperature all of the fat would come out of the butter then resulting in a greasy dough, difficult to handle and roll.
Sugar: the sugar normally used for pasta frolla is the refined saccharose (the common white sugar), that can be used both in the granulated or icing form. It is important to take into consideration that the granulated version, since for its structure remains in suspension into the dough, enable gluten development that means a more elastic dough; on the contrary icing sugar becomes part of the dough's structure which is therefore more friable. Not really an easy statement, but in few words icing sugar gives a more crumbly pastry.
As for the butter, also for sugar there is no optimal quantity: on average sugar is 40% of flour weight. Increasing or decreasing the quantity will produce a more or less crunchy dough: in fact sugar, while baking, at the beginning melts then starts to caramelize: this process on one side lends a brown color to the dough, on the other gives it a crunchy texture. It is recommended to use a quantity of sugar between 25% and 60% of the flour weight, in order to avoid unpleasant caramelization. There are also varieties of pasta frolla, used for specific recipes, made with unrefined cane sugar or honey or sugar alternatives (like stevia).
When using granulated sugar, pasta frolla is called "comune" (meaning basic, ordinary); when made with icing sugar it is called "fine" (meaning more friable).
Eggs: eggs are the last ingredient of pasta frolla and represent the liquid component; some recipes use only yolks, others whole eggs, others only whites. Yolks, which contain a high percentage of fats, add fat to the total quantity in the recipe then increasing the friable, crumbly texture of the pastry. If a more elastic dough is needed, for facilitating the handling when lining pans or moulds with particular forms, whole eggs are recommended. In fact egg whites (which contain about 88% water) make the gluten react then creating a more elastic dough; in addition to this, whole eggs tend to make the dough rise while baking, thanks to the presence of proteins in the white: the final result will be a more crunchy and dry pastry. For particular purposes eggs can be substituted by a different liquid, such as cream, milk or even water, with a different final texture.
To be precise, eggs quantity / weight should be calculated with particular coefficients, which depend on the type of sugar and egg (yolk, whole or white) used in the recipe: the ratio between the weight of flour+butter+ sugar (that is the dough base) and the coefficient will give the weight of eggs to be used. Got an headache? Don't worry; just nod, pretending that everything is clear and completely understood. Seriously speaking, and to simplify everything, in general for a pasta frolla (for tartes and pies, not the whipped one) made using 500 g butter for each 1 kg flour, the weight of eggs (or yolks only) can be calculated as total weight flour+butter+sugar : 10.
Finally flavors can be added to the dough: vanilla seeds or vanilla extract are very common, but I like to add also lemon zest whose fresh and tangy flavor, in my opinion, perfectly balances the richness of butter and eggs. Other flavor can alternatively be used, depending on the filling / use of the dough: almond extract, orange or other citrus zest, ginger, etc.
Besides the type and quantity of ingredients, there are different techniques for making the dough; in any case it is important to handle the dough as less as possible in order to avoid gluten development and consequently a tough, too elastic pastry. Seven minutes should be enough to produce a perfect pastry.
Three are the possible techniques:
1. Classic technique
2. Sablè technique
3. Whipped technique
The first two methods are used when the pastry will be used for tartes, tartelettes and pies, the third one when pasta frolla will have to be shaped using a piping bag, that is for making cookies or lining pans with particular shapes.
Classic technique: butter is mixed with sugar, then eggs are incorporated; flour and flavors are added only in the end.
Sablè or crumble technique: flour and butter are mixed in order to obtain a crumbly, sand-like mixture. Thanks to this step, fat molecules cover flour and make it waterproof thus avoiding that it will absorb liquid ingredients (mainly eggs) during the following preparation steps and baking: the final pastry will therefore be much more friable than in the traditional technique. Sugar is added afterwards, then flavors and eggs.
In both techniques it is important to let the dough rest in a cold place before rolling it out: the butter, which was at room temperature and diced, has to solidify and the flour, which was rendered more elastic by the addition of the liquids, needs to lose some of that elasticity. The ball of pastry should be wrapped in plastic and refrigerated for at least 4 to 5 hours (24 hours are optimal, 1 hour the minimum).
It is also possible, and I recommend to proceed this way, to make up several batches at the one time and freeze them, well wrapped in plastic, for more than 1 month. When ready to use the pastry, transfer it to the refrigerator to defrost a day before using it. Before using remember to work the dough on a slighlty floured surface just enough to make it elastic and easy to roll.
Whipped technique: butter is whisked until soft and creamy then icing sugar is added and the two ingredient are whisked together at higher speed until the mixture is almost foamy and white. Then eggs at room temperature are added and incorporated; finally flour is mixed in. Unlike in previous techniques, this dough should be used immediately to form cookies or line moulds; at this point the dough should rest before baking in order to stabilize butter and preserve the desired shape.
Excluding the whipped pasta frolla, after the dough has been left to rest, you should sprinkle a counter lightly with flour - be careful as too much flour will alter the ideal ratio of flour to butter - and roll it out using a rolling pin. The pastry can also become overheated or overworked at this stage, which means it will tend either to break up or to stick. If this happens, you can solve the problem by adding a few tablespoons of cold water or half an egg white to the dough. If the pastry tears while you’re rolling it out, you can easily patch up the tears once it is in the tart pan and they won't be noticeable when the tart has been filled and baked. The important thing is not to leave any hole, even small, otherwise the filling will go out of the cake. It is recommended to butter the pan, not to avoid that the pastry sticks on it but because fat is an heat conductor and then will help the pastry to bake homogeneously.
The pastry can then be baked blind and filled afterwards (for example if the filling is custard and fresh fruit or chocolate mousse/ganache) or filled then baked (this is the case of pies or other fillings that have to be baked). In some recipes the shell is blind baked, then filled - and sometimes decorated with more unbaked dough- and baked again until everything is cooked through.
In any case, once baked, the pastry should be golden, but still soft: it will crisp up slightly as it cools
But, let's go back to the recipe for crostata alla marmellata, the most simple of all possible crostata.
After all I said, it is obvious that there are countless possible recipes for pasta frolla. Of course I have tried many of them (including, ça va sans dire, my mother's recipe), and never stop trying different and new versions.
But, among the recipes that I have already tried, I have some favorites. And these are the recipes I make more often, especially when I want to be sure that the result will be good. The recipe I used this time for my crostata - and that I am going to share - belongs to this list and, so far as I have experimented, it is one of the most versatile, being perfect for a simple filling like jam or marmalade as well as for more complex tartes, even those intended to be served in special occasion (e.g. tarte filled with chocolate mousse or ganache and decorated with red fruit or with a shiny chocolate glaze). It is made using icing sugar which gives a wonderful melt-in-the-mouth texture: these characteristic makes it perfect when the shell is first blind baked and then filled with something soft and creamy (have you ever been served a tempting slice of fruit and custard tarte whose base you didn't know how to break, being as hard as a piece of rock? Embarrassing, especially if it's you to serve something like this!). Talking about eggs, this pastry contains mainly yolks plus a limited quantity of whites which add a bit of elasticity, making the dough easier to handle and roll. Considering the baking technique, the crostata alla marmellata is not traditionally blind baked: the pan is lined with the pastry, the jam is spread all over the unbaked shell, the top is decorated with strips of pastry and finally baked. But I read somewhere that some pastry chefs recommend to blind bake the shell also when the filling is jam: this prevents the jam from cooking for too long (fruit is already cooked) and becoming sticky and hard. I tried this technique a couple of time and I have to say that the result was very satisfying, probably better than in the traditional method: if you are not in a hurry, I would recommend to go with this technique (see update below). But in this case, it is better to let the crostata rest for at least 12 to 18 hours before eating, so that the shell can "absorb" jam and all flavors are well amalgamated (actually, in my opinion all types of crostata are better one day after preparation).
And now I finally stop writing about theory and give this recipe for pasta frolla (more will come in future) and crostata alla marmellata.

Crostata alla marmellata (jam tarte)

Crostata alla marmellata (jam tarte)
makes two 20 cm Æ tartes  
Pasta frolla:
500 g pastry or cake flour, or Italian flour 00 (alternatively 460 g all-purpose flour + 40 g corn starch)
250 g butter, chilled and cubed
140 g icing sugar
3 egg yolks
1 whole egg
zest of 1 large lemon (organic, not waxed, if possible)
seed of 1 vanilla bean (or 2 tsp pure vanilla extract)
your favorite jam or marmalade (about 250 g for each 20 Æ cm tarte)

Sift the flour in a large mixing bowl. Add in the cubed butter and, using your fingertips, rub the butter into the flour until you get a crumbly mixture and there are no more visible pieces of butter.  
Crostata alla marmellata (jam tarte)_making the dough

Mix in the icing sugar (sifted through a colander if it contains granules) and then lemon zest.  Lightly beat the egg yolks and whole egg with a pinch of salt and the vanilla seeds or extract. Using a knife, mix the beaten eggs into the flour - butter mixture until the pastry comes together into a smooth, elastic ball.
When preparing the pastry it is important that everything is cold (the ideal temperature is 13°C): keep your hands cool, or use the blades of two knives or a pastry scrapers for mixing the ingredients; alternatively ingredients can be mixed using a food processor.
Once the dough comes into a ball, wrap it in plastic film and refrigerated for one day (if you can't wait so long, keep the dough in the fridge for at least 1 hour).
Crostata alla marmellata (jam tarte)_the dough

Preheat the oven to 180°C.
After resting, on a slightly floured counter -  be careful since too much flour will alter the ideal ratio of flour to butter -  rapidly work then roll out half of the pastry 1 to 4 - 5 mm thickness and use it to line a buttered and floured 20 cm round tart pan (I recommend to make a thicker border for the tart by rolling the excess pastry into a thin rope, then placing it around the edges of the tart pan). Prick the base with a fork, line it with baking paper, fill it with baking beans (or rice) and blind-bake for 15 minutes. 
Crostata alla marmellata (jam tarte)

Then remove the baking paper and beans and let cool 2.
In the meantime  roll out the excess pastry and cut into strips, about 1cm wide to create a lattice for the top of your tarts. Chill for about 10 minutes: it will be easier to handle when you go to transfer them onto the crostata.
When the pastry base is cold, fill the tarts with your favorite jam (don't be shy, the jam layer should be thick) and place lattice strips over the top. 
Crostata alla marmellata (jam tarte)
Bake at 180°C for another 15 minutes or until golden on top. Once baked, the pastry should be golden, but still soft: it will crisp up slightly as it cools. Let cool in the pan before transferring to a serving plate.

1 The remaining pastry, if not all is used straight away, can be frozen well wrapped in plastic, for up to 1 month. When you are ready to use the frozen pastry, transfer it to the refrigerator to defrost at least 6 hours in advance.
2 The blind baking is optional for the crostata alla marmellata but allows to cook the jam for a limited time, then avoiding it becomes dry and sticky; traditionally the pastry base is filled with jam when still unbaked, then decorated with strips and baked at 180°C for about 30 minutes until the pastry is golden on the edges.
Update (11 March 2015)
After publishing this recipet I made this crostata several other times, using both the blind baking and the traditional technique where the dough is filled then baked and I have to say that I prefer the result of the traditional method (that is even quicker). I will reserve the blind baking just to fillings different than simple jam.

And if you have some leftover of the dough? Roll it again and cut out some cookies - or frollini as I would say in Italian!
Crostata alla marmellata (jam tarte)_frollini

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